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Geologic Monitoring


Photo of Soil sampling in Denali National Park and Preserve
A researcher collects soil samples to study impacts of melting permafrost in Denali National Park and Preserve.

What is permafrost?

Permafrost is ground that remains at or below 0 °C for at least two consecutive years. Permafrost resides beneath a surficial "active layer" that freezes and thaws each year.

Most permafrost is located in high latitudes. Approximately 80% of Alaska is underlain by permafrost. But mountain permafrost may exist at high altitudes in lower latitudes, such as in western North America and on Mount Washington in New Hampshire.

Why does the National Park Service monitor permafrost?

The condition of permafrost is of interest to the National Park Service for two primary reasons.

  • Because ice helps to bond slope deposits, landslides and thaw slumps are expected to occur in mountainous areas if the permafrost thaws.
  • Permafrost impedes subsurface drainage, creating wet to moist conditions that provide good habitat for many alpine plant species. Thawing of permafrost would increase drainage and dry the soil, thus impacting the vegetation.
  • Monitoring Book
  • Resource Facts
  • Case Study

Geological Monitoring Book

Vital Signs Monitored

  1. Thermal state
  2. Physical conditions

Chapter 9
Permafrost Conditions and Processes (PDF - 1.49MB)

The current permafrost in Alaska appears to have been initiated during the climatic cooling that began ~2.5 million years ago. The climatic changes of the past century coupled with recent observations of warming and thawing permafrost have caused concern about the future of permafrost.

NPS Permafrost Facts

Permafrost is found in 10 of Alaska's 16 national parks.

Monitoring Permafrost Conditions in the National Park Service

Case study coming soon...

Related Links



Last Updated: January 03, 2017